2 * This file is part of the libserialport project.
4 * Copyright (C) 2013 Martin Ling <martin-libserialport@earth.li>
6 * This program is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU Lesser General Public License as
8 * published by the Free Software Foundation, either version 3 of the
9 * License, or (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU Lesser General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
22 * @mainpage libserialport API
27 * libserialport is a minimal library written in C that is intended to take
28 * care of the OS-specific details when writing software that uses serial ports.
30 * By writing your serial code to use libserialport, you enable it to work
31 * transparently on any platform supported by the library.
33 * The operations that are supported are:
35 * - @ref Enumeration (obtaining a list of serial ports on the system)
37 * - @ref Configuration (baud rate, parity, etc.)
41 * libserialport is an open source project released under the LGPL3+ license.
46 * The API is simple, and designed to be a minimal wrapper around the serial
47 * port support in each OS.
49 * Most functions take a pointer to a struct sp_port, which represents a serial
50 * port. These structures are always allocated and freed by the library, using
51 * the functions in the @ref Enumeration "Enumeration" section.
53 * All functions can return only three possible error values. @ref SP_ERR_ARG
54 * indicates the function was called with invalid arguments. @ref SP_ERR_FAIL
55 * indicates that the OS reported a failure. @ref SP_ERR_MEM indicates that a
56 * memory allocation failed. All of these error values are negative.
58 * When @ref SP_ERR_FAIL is returned, an error code or string description of
59 * the error can be obtained by calling sp_last_error_code() or
60 * sp_last_error_message(). The error code or message is that provided by the
61 * OS; libserialport does not define any error codes or messages of its own.
63 * Function calls that succeed return @ref SP_OK, which is equal to zero,
64 * or where otherwise documented a positive value.
67 #ifndef LIBSERIALPORT_H
68 #define LIBSERIALPORT_H
79 /* Package version macros (e.g. for conditional compilation). */
80 #define SP_PACKAGE_VERSION_MAJOR @SP_PACKAGE_VERSION_MAJOR@
81 #define SP_PACKAGE_VERSION_MINOR @SP_PACKAGE_VERSION_MINOR@
82 #define SP_PACKAGE_VERSION_STRING "@SP_PACKAGE_VERSION@"
84 /* Library/libtool version macros (e.g. for conditional compilation). */
85 #define SP_LIB_VERSION_CURRENT @SP_LIB_VERSION_CURRENT@
86 #define SP_LIB_VERSION_REVISION @SP_LIB_VERSION_REVISION@
87 #define SP_LIB_VERSION_AGE @SP_LIB_VERSION_AGE@
88 #define SP_LIB_VERSION_STRING "@SP_LIB_VERSION@"
92 /** Operation completed successfully. */
94 /** Invalid arguments were passed to the function. */
96 /** A system error occured while executing the operation. */
98 /** A memory allocation failed while executing the operation. */
102 /** Port access modes. */
104 /** Open port for read access. */
106 /** Open port for write access. */
108 /** Open port in non-blocking mode. */
109 SP_MODE_NONBLOCK = 4,
112 /** Buffer selection. */
116 /** Output buffer. */
122 /** Parity settings. */
124 /** Special value to indicate setting should be left alone. */
125 SP_PARITY_INVALID = -1,
134 /** RTS pin behaviour. */
136 /** Special value to indicate setting should be left alone. */
142 /** RTS used for flow control. */
143 SP_RTS_FLOW_CONTROL = 2,
146 /** CTS pin behaviour. */
148 /** Special value to indicate setting should be left alone. */
152 /** CTS used for flow control. */
153 SP_CTS_FLOW_CONTROL = 1,
156 /** DTR pin behaviour. */
158 /** Special value to indicate setting should be left alone. */
164 /** DTR used for flow control. */
165 SP_DTR_FLOW_CONTROL = 2,
168 /** DSR pin behaviour. */
170 /** Special value to indicate setting should be left alone. */
174 /** DSR used for flow control. */
175 SP_DSR_FLOW_CONTROL = 1,
178 /** XON/XOFF flow control behaviour. */
180 /** Special value to indicate setting should be left alone. */
181 SP_XONXOFF_INVALID = -1,
182 /** XON/XOFF disabled. */
183 SP_XONXOFF_DISABLED = 0,
184 /** XON/XOFF enabled for input only. */
186 /** XON/XOFF enabled for output only. */
188 /** XON/XOFF enabled for input and output. */
189 SP_XONXOFF_INOUT = 3,
192 /** Standard flow control combinations. */
193 enum sp_flowcontrol {
194 /** No flow control. */
195 SP_FLOWCONTROL_NONE = 0,
196 /** Software flow control using XON/XOFF characters. */
197 SP_FLOWCONTROL_XONXOFF = 1,
198 /** Hardware flow control using RTS/CTS signals. */
199 SP_FLOWCONTROL_RTSCTS = 2,
200 /** Hardware flow control using DTR/DSR signals. */
201 SP_FLOWCONTROL_DTRDSR = 3,
204 /** Input signals. */
206 /** Clear to send. */
208 /** Data set ready. */
210 /** Data carrier detect. */
212 /** Ring indicator. */
216 /** A serial port. */
218 /** Name used to open the port. */
221 /** OS-specific port handle. */
230 /** Configuration for a serial port. */
231 struct sp_port_config {
232 /** Baud rate in bits per second. */
234 /** Number of data bits to use. Valid values are 5 to 8. */
236 /** Parity setting to use. */
237 enum sp_parity parity;
238 /** Number of stop bits to use (1 or 2). */
248 /** XON/XOFF flow control mode. */
249 enum sp_xonxoff xon_xoff;
253 @defgroup Enumeration Port enumeration
258 * Obtain a pointer to a new sp_port structure representing the named port.
260 * The user should allocate a variable of type "struct sp_port *" and pass a
261 * pointer to this to receive the result.
263 * The result should be freed after use by calling sp_free_port().
265 * @return SP_OK on success, SP_ERR_FAIL on failure, SP_ERR_MEM on allocation
266 * failure, or SP_ERR_ARG if an invalid pointer is passed. If any error
267 * is returned, the variable pointed to by port_ptr will be set to NULL.
268 * Otherwise, it will be set to point to the newly allocated port.
270 enum sp_return sp_get_port_by_name(const char *portname, struct sp_port **port_ptr);
273 * Free a port structure obtained from sp_get_port_by_name() or sp_copy_port().
275 void sp_free_port(struct sp_port *port);
278 * List the serial ports available on the system.
280 * The result obtained is an array of pointers to sp_port structures,
281 * terminated by a NULL. The user should allocate a variable of type
282 * "struct sp_port **" and pass a pointer to this to receive the result.
284 * The result should be freed after use by calling sp_free_port_list().
285 * If a port from the list is to be used after freeing the list, it must be
286 * copied first using sp_copy_port().
288 * @return SP_OK on success, SP_ERR_FAIL on failure, SP_ERR_MEM on allocation
289 * failure, or SP_ERR_ARG if an invalid pointer is passed. If any error
290 * is returned, the variable pointed to by list_ptr will be set to NULL.
291 * Otherwise, it will be set to point to the newly allocated array.
293 enum sp_return sp_list_ports(struct sp_port ***list_ptr);
296 * Make a new copy of a sp_port structure.
298 * The user should allocate a variable of type "struct sp_port *" and pass a
299 * pointer to this to receive the result.
301 * The copy should be freed after use by calling sp_free_port().
303 * @return SP_OK on success, SP_ERR_MEM on allocation failure, or SP_ERR_ARG
304 * if an invalid port or pointer is passed. If any error is returned,
305 * the variable pointed to by copy_ptr will be set to NULL. Otherwise,
306 * it will be set to point to the newly allocated copy.
308 enum sp_return sp_copy_port(const struct sp_port *port, struct sp_port **copy_ptr);
311 * Free a port list obtained from sp_list_ports().
313 * This will also free all the sp_port structures referred to from the list;
314 * any that are to be retained must be copied first using sp_copy_port().
316 void sp_free_port_list(struct sp_port **ports);
320 * @defgroup Ports Opening and closing ports
325 * Open the specified serial port.
327 * @param port Pointer to port structure.
328 * @param flags Flags to use when opening the serial port.
330 * @return SP_OK on success, SP_ERR_FAIL on failure, SP_ERR_MEM on allocation
331 * failure, or SP_ERR_ARG if an invalid port is passed.
333 enum sp_return sp_open(struct sp_port *port, enum sp_mode flags);
336 * Close the specified serial port.
338 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
339 * if an invalid port is passed.
341 enum sp_return sp_close(struct sp_port *port);
345 * @defgroup Configuration Setting port parameters
350 * Get the current configuration of the specified serial port.
352 * The user should allocate a struct sp_port_config, then pass a pointer to it
353 * as the config parameter. The struct will be populated with the port
356 * Any setting that is in a state not recognised or supported by
357 * libserialport will have its value set to -1 in the struct.
359 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
360 * for invalid arguments.
362 enum sp_return sp_get_config(struct sp_port *port, struct sp_port_config *config);
365 * Set the configuration for the specified serial port.
367 * The user should populate a struct sp_port_config, then pass a pointer to it
368 * as the config parameter.
370 * To retain the current value of any setting, set that field to -1.
372 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
373 * for invalid arguments.
375 enum sp_return sp_set_config(struct sp_port *port, const struct sp_port_config *config);
378 * Set the baud rate for the specified serial port.
380 * @param port Pointer to port structure.
381 * @param baudrate Baud rate in bits per second.
383 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
384 * for invalid arguments.
386 enum sp_return sp_set_baudrate(struct sp_port *port, int baudrate);
389 * Set the number of data bits for the specified serial port.
391 * @param port Pointer to port structure.
392 * @param bits Number of data bits to use. Valid values are 5 to 8.
394 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
395 * for invalid arguments.
397 enum sp_return sp_set_bits(struct sp_port *port, int bits);
400 * Set the parity for the specified serial port.
402 * @param port Pointer to port structure.
403 * @param parity Parity setting to use.
405 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
406 * for invalid arguments.
408 enum sp_return sp_set_parity(struct sp_port *port, enum sp_parity parity);
411 * Set the number of stop bits for the specified port.
413 * @param port Pointer to port structure.
414 * @param stopbits Number of stop bits to use (1 or 2).
416 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
417 * for invalid arguments.
419 enum sp_return sp_set_stopbits(struct sp_port *port, int stopbits);
422 * Set the flow control type for the specified serial port.
424 * This function is a wrapper that sets the RTS, CTS, DTR, DSR and
425 * XON/XOFF settings as necessary for the specified flow control
426 * type. For more fine-grained control of these settings, use their
427 * individual configuration functions or the sp_set_config() function.
429 * @param port Pointer to port structure.
430 * @param flowcontrol Flow control setting to use.
432 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
433 * for invalid arguments.
435 enum sp_return sp_set_flowcontrol(struct sp_port *port, enum sp_flowcontrol flowcontrol);
438 * Set the RTS pin behaviour for the specified port.
440 * @param port Pointer to port structure.
441 * @param rts RTS pin mode.
443 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
444 * for invalid arguments.
446 enum sp_return sp_set_rts(struct sp_port *port, enum sp_rts rts);
449 * Set the CTS pin behaviour for the specified port.
451 * @param port Pointer to port structure.
452 * @param cts CTS pin mode.
454 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
455 * for invalid arguments.
457 enum sp_return sp_set_cts(struct sp_port *port, enum sp_cts cts);
460 * Set the DTR pin behaviour for the specified port.
462 * @param port Pointer to port structure.
463 * @param dtr DTR pin mode.
465 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
466 * for invalid arguments.
468 enum sp_return sp_set_dtr(struct sp_port *port, enum sp_dtr dtr);
471 * Set the RTS pin behaviour for the specified port.
473 * @param port Pointer to port structure.
474 * @param dsr DSR pin mode.
476 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
477 * for invalid arguments.
479 enum sp_return sp_set_dsr(struct sp_port *port, enum sp_dsr dsr);
482 * Configure XON/XOFF flow control for the specified port.
484 * @param port Pointer to port structure.
485 * @param xon_xoff XON/XOFF flow control mode.
487 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
488 * for invalid arguments.
490 enum sp_return sp_set_xon_xoff(struct sp_port *port, enum sp_xonxoff xon_xoff);
494 * @defgroup Data Reading, writing, and flushing data
499 * Read bytes from the specified serial port.
501 * Note that this function may return after reading less than the specified
502 * number of bytes; it is the user's responsibility to iterate as necessary
505 * @param port Pointer to port structure.
506 * @param buf Buffer in which to store the bytes read.
507 * @param count Maximum number of bytes to read.
509 * @return The number of bytes read, SP_ERR_FAIL on failure,
510 * or SP_ERR_ARG for invalid arguments.
512 enum sp_return sp_read(struct sp_port *port, void *buf, size_t count);
515 * Write bytes to the specified serial port.
517 * Note that this function may return after writing less than the specified
518 * number of bytes; it is the user's responsibility to iterate as necessary
521 * @param port Pointer to port structure.
522 * @param buf Buffer containing the bytes to write.
523 * @param count Maximum number of bytes to write.
525 * @return The number of bytes written, SP_ERR_FAIL on failure,
526 * or SP_ERR_ARG for invalid arguments.
528 enum sp_return sp_write(struct sp_port *port, const void *buf, size_t count);
531 * Flush serial port buffers. Data in the selected buffer(s) is discarded.
533 * @param port Pointer to port structure.
534 * @param buffers Which buffer(s) to flush.
536 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
537 * if an invalid port is passed.
539 enum sp_return sp_flush(struct sp_port *port, enum sp_buffer buffers);
542 * Wait for buffered data to be transmitted.
544 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
545 * if an invalid port is passed.
547 enum sp_return sp_drain(struct sp_port *port);
551 * @defgroup Signal Port signalling operations
556 * Gets the status of the control signals for the specified port.
558 * The user should allocate a variable of type "enum sp_signal" and pass a
559 * pointer to this variable to receive the result. The result is a bitmask
560 * in which individual signals can be checked by bitwise OR with values of
561 * the sp_signal enum.
563 * @param port Pointer to port structure.
564 * @param signals Pointer to variable to receive result.
566 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
567 * if an an invalid port or pointer is passed.
569 enum sp_return sp_get_signals(struct sp_port *port, enum sp_signal *signals);
572 * Put the port transmit line into the break state.
574 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
575 * if an invalid port is passed.
577 enum sp_return sp_start_break(struct sp_port *port);
580 * Take the port transmit line out of the break state.
582 * @return SP_OK on success, SP_ERR_FAIL on failure, or SP_ERR_ARG
583 * if an invalid port is passed.
585 enum sp_return sp_end_break(struct sp_port *port);
589 * @defgroup Errors Obtaining error information
594 * Get the error code for a failed operation.
596 * In order to obtain the correct result, this function should be called
597 * straight after the failure, before executing any other system operations.
599 * @return The system's numeric code for the error that caused the last
602 int sp_last_error_code(void);
605 * Get the error message for a failed operation.
607 * In order to obtain the correct result, this function should be called
608 * straight after the failure, before executing other system operations.
610 * @return The system's message for the error that caused the last
611 * operation to fail. This string may be allocated by the function,
612 * and should be freed after use by calling sp_free_error_message().
614 char *sp_last_error_message(void);
617 * Free an error message returned by sp_last_error_message().
619 void sp_free_error_message(char *message);
627 #endif /* LIBSERIALPORT_H */